The going theory is your towels should be washed around every three to four uses.

But new research has found the vast majority of towels hanging on our bathroom racks are contaminated with potentially harmful disease-causing bacteria.

Dr Charles Gerba, a microbiologist at the University of Arizona, recently spoke with US publication Time, on his new research for a yet-to-be published study.

He found nearly 90 percent of towels were contaminated with coliform bacteria. These organisms can indicate the presence of disease-causing bacteria in water.

Worryingly, around 14 percent carried E. Coli, and some even carried traces of salmonella.

"After about two days, if you dry your face on a hand towel, you're probably getting more E. coli on your face than if you stuck your head in a toilet and flushed it," he told the publication.

He found the germs are transferred mostly through drying our hands after not being wash thoroughly.

But before you take all of your towels outside, stack them in a pile, and burn them to the ground, Susan Whittier, director of clinical microbiology at New York-Presbyterian and Columbia University Medical Centre says it's not a dangerous as it sounds.

Our bodies live in an environment full of microbes so using your own towel, covered in your own bacteria, is unlikely to make you ill. Even sharing someone else's towel leaves a slim chance of getting sick from their germs.

"As long as it's drying completely between use, there's almost no chance of passing bacteria from one person to another."

The risk of contracting an illness from your towel comes when you have open cuts, abrasions or very dry skin, as microbes are more likely to get into your system.

Gerba says to stay on the safe side wash your towels every two uses and with hot water and oxygen bleach.